The field of the disclosure relates generally to turbofan engines and, more particularly, to systems and methods of scavenging lubricating fluid within a turbofan engine.
At least some known gas turbine engines, such as turbofan engines, include a fan, a core engine, and a power turbine. The core engine includes at least one compressor, a combustor, and a high-pressure turbine coupled together in a serial flow relationship. More specifically, the compressor and high-pressure turbine are coupled through a first drive shaft to form a high-pressure rotor assembly. Air entering the core engine is mixed with fuel and ignited to form a high energy gas stream. The high energy gas stream flows through the high-pressure turbine to rotatably drive the high-pressure turbine such that the shaft rotatably drives the compressor. The gas stream expands as it flows through a power or low-pressure turbine positioned aft of the high-pressure turbine. The low-pressure turbine includes a rotor assembly having a fan coupled to a second drive shaft. The low-pressure turbine rotatably drives the fan through the second drive shaft.
The drive shafts in the turbofan engine are typically supported by one or more bearings, and at least some known turbofans include a speed-reducing gearbox coupled along the drive shaft between the low-pressure turbine and the fan. The gearbox facilitates decoupling the fan tip speed from the speed of the low-pressure turbine. Lubricating fluid, such as oil, is typically provided to the shaft bearings and to the gearbox during operation of the turbofan engine. The lubricating fluid facilitates lubricating the shaft bearings and the gearbox, and also facilitates removing heat therefrom. More specifically, the lubricating fluid is typically discharged from the components being lubricated, scavenged from a fan frame cavity within the turbofan engine, and is recirculated for continued use therein. At least some known fan frames include bolt-on scoops for scavenging the lubricating fluid from the fan frame cavity. However, radial space within the fan frame cavity is generally limited, such that reducing the radial height of components positioned within the fan frame cavity is desirable.